BeOS may be dead, but over a decade after its lamentable demise the open source Haiku project keeps its legacy alive. Haiku is an attempt to build a drop-in, binary compatible replacement for BeOS, as well as extending the defunct OS's functionality and support for modern hardware. At least, that's the short-term goal - eventually, Haiku is intended significantly enhance BeOS while maintaining the same philosophy of simplicity and transparency, and without being weighed down with the legacy code of many other contemporary operating systems. Computerworld Australia recently caught up with Stephan Assmus, who has been a key contributor to the project for seven years for a lengthy chat about BeOS, the current state of Haiku and the project's future plans.

but the haiku at the moment says: we finish R1, then we continue with R2.
But they could do something different. They could already now start working on R2 while also working on R1. And if something in R2 would be important to R1, it can be ported back to R1. For example while R1 is not finished, the R1 version could be the "official release", and the R2 would be just something like a prototype which doesnt need to be backward compatible with each release. And just after R1 is finished, the R2 becomes the "official version", which from there on needs to be backward compatible and not break api/abi. This kind of "freedom" perhaps could help to make greater progress and to come-up with new ideas.
There should something like an "experimental haiku", in my vision.